In my opinion, there’s a big problem with attempting to turn an iPod into an audiophile-quality product. Let’s assume that you have an iTunes playlist comprised of music from many sources, meaning that the volume levels of the original recordings will vary widely. If you’re serious about preserving the dynamics of the original recording, you will NOT want to use the Soundcheck feature in iTunes or in the iPod.
You can manually adjust the levels of recordings imported to iTunes, so if you’re using your computer as your music source, no problem. However, when you transfer your playlists from iTunes to the iPod, guess what? All that fine-tuning you’ve done to get all the tracks in the playlist to play at appropriate levels is all for naught. NONE of the adjustments you make to iTunes are transferred over to the iPod.
So, you’re still stuck with having to use the Soundcheck feature on the iPod unless you want to be constantly adjusting the iPod’s volume level. Or, if you’ve hooked-up the iPod to the main stereo in the house for a party, you either have to use the Soundcheck on the iPod, ruining the dynamics of your very expensive home stereo, or else spend your time with remote in hand constantly adjusting the volume for each track. Bummer.
For some reason, Apple continues use its iPod and iTunes software updates to add (in my opinion) silly gimmicky features, instead of resolving a fundamental problem that should matter to anyone concerned about sound quality. I can only assume that Apple doesn’t care about enticing audiophiles to buy iPods, figuring there aren't enough of us to matter.
All that to say, I think I’d be wasting my money paying to have the iPod’s potential enhanced while knowing that its increased potential can never be fully realized.